A grand show is promised for the last Indianapolis 500 of the millennium. Winning the Indy 500 requires a star driver taking main stage, of course, but an Indy Racing League (IRL) car is more than a mere prop. The machine must be as safe and efficient as possible in a race where fractions of a second count and one wrong move can result in devastating injuries. Out of the limelight is a supporting cast of engineers, team mechanics, researchers, and manufacturers who may deserve equal billing with drivers.
The IRL, bound by the age-old tradition of the Indy 500 race, was founded by Indianapolis Motor Speedway president Tony George with 1996 marking the inaugural IRL racing season. The Indianapolis 500 requires six to eight pit stops, so precisely engineered equipment and well-orchestrated pit stops are imperative.
“There’s a growing interest in the IRL. People now are realizing that IRL and CART will probably not get together, so if they want to be involved at Indy, they have to do a specific engine package for the IRL,” says Joe Negri, GM Motorsports, Warren, Mich.
As a new millennium dawns, so does a new Indy car. Regulations for a car to run from 2000 to 2004 call for a smaller engine displacement and a redesigned chassis. More subtle changes for the brickyard race include updates to the track and new safety features.
Gentlemen, start your engines
This year could be the last year for the IRL’s voracious roar, as next season engine makers will have the option of sticking with the current two-plane crankshaft or changing to a flat plane, or single-plane crankshaft. The new crankshaft will alter the pitch and tone of the engine significantly, according to the IRL. Frank Honsowetz, manager for Nissan Motorsports, Gardena, Calif., notes that there are pros and cons to each, but that for pure horsepower, the flat plane will probably prove to be better. Not optional in 2000, is an IRL-mandated switch from a 4.0 to a 3.5-liter engine. The methanol-fueled engines for 2000 will no longer have to be production based, but a fixed cost will still remain in effect.
The IRL also has lowered the cap on speed with its rev limiter. Phil Casey, IRL technical director, explains, “It was 10,500 rpm for the first two years, and we’ve reduced it to 10,300 to help reliability. The rev limiter is used to make sure the competition isn’t running something higher than 10,300.” The limiter is incorporated into the same wiring harness as the main computer, but it’s a separate device to prevent tampering.
“The IRL is looking to reduce the speeds somewhat. We felt that we had our engine very reliable, but dropping to 10,300 will no doubt improve the reliability even more. So we were in favor of the change to drop the rpm,” says Negri.
“These new engine regulations have many advantages,” says Leo Mehl, executive director of the IRL. “All of our current engines can be updated economically, engine costs and reliability will be enhanced, and the sound of the engine will be more pleasant.”
The two IRL-approved engines, the Oldsmobile Aurora and the Nissan Infiniti, enter the 1999 season tweaked for performance. The cylinder block in the Infiniti was contoured, giving it a more rounded shape. Nissan has trimmed what Honsowetz calls “parasitic losses” by reducing the amount of oil flowing through the engine, as any air or oil that comes in contact with the crankshaft at 200 mph wastes power.
For 1999, GM Motorsports has made changes to the Aurora cylinder block as well as head castings and cams.
“The main effort that we’ve had on the Oldsmobile since the start is just that we’ve continued to make small changes to improve reliability and durability,” says Negri. Any cylinder head and block will reach a certain point at which it develops cracks. GM has focused on making improvements such as reducing stress and adding materials.
“There probably isn’t a part out there, or very few parts, that every time you run a new batch you don’t make a minor change,” says Negri.
Teams must be prepared to handle engine failure despite all planning. They typically plan for one engine change a race, but things don’t always go as planned. At the Atlanta 500 Classic last August, the Panther Racing team had to replace the Aurora engine in Scott Goodyear’s car between morning practice and qualifying. In an hour and a half the Panther Racing team had replaced the engine. Then, during a prerace practice the next day, the engine developed some vibration. So, they replaced the engine again before the race.
“You don’t normally put that many miles on a car on a Saturday, and that same engine is suitable for the race. By the end of the race it may become a little bit tired, so we practice with that engine the next race,” says Andy Brown, chief engineer, Panther Racing. Goodyear took the car to a fourth place finish on the third engine.
Currently, the Aurora is the dominant choice of the series, but Nissan is optimistic that its new Infiniti engine meeting regulations for 2000 to 2004 will change that.
“I think it’s fully agreed amongst the IRL fraternity and family that we’re as good as, maybe even better than the competition,” says Honsowetz, “but we’re outnumbered because a majority of the competitors own an inventory of engines. So our next goal is to get good teams to convert.” Last summer, Roberto Guerrero of the CVR Cobb Racing team switched to the Infiniti. Honsowetz says, “With Roberto driving, we stepped up a level in the quality of driver using our engine.”
Guerrero used the phase 2.5 Infiniti powerplant to post an unofficial lap time of 21.02 sec, the second quickest among IRL drivers who tested before the Indy 200 at the Walt Disney World Speedway in Orlando in December and January. Scott Goodyear set the winning test lap time of 21.00 sec. Guerrero, however, faced handling problems during the race, contributed to by a section of another car’s wing becoming wedged beneath his car’s lower body. He finished in 13th place.
“To be honest, the engine was very good all weekend, but the handling of our car prevented us from showing how good it really was,” says Guerrero.
“We have a complete, newly-designed engine that we had originally planned on introducing this year. When they announced the rule change, which we knew was coming, we decided to wait. We are currently reconfiguring that engine to be a specific 3.5-liter design,” says Honsowetz.
Air Indy
Increasing down force and eliminating drag is the name of the game in chassis design. The three chassis manufacturers, Dallara, G Force Precision Engineering Ltd., England, and Riley & Scott, Indianapolis, have honed their designs in pursuit of a more aerodynamic shape. These designs sell to teams for up to $280,000 a pop. The main tub of the chassis remains the same for 1999, but subtle aerodynamic changes are made in less expensive update kits featuring add-ons such as an underwing, air box, engine cover, and side pods which attach to the main tub.
“We’ve made small changes to the aerodynamics to provide slightly less drag and a little more down force which will improve the performance slightly,” says Garrett.
IRL changes call for a bigger, thicker headrest pad which requires modifications to the tub. Dallara is planning to alter the cockpit for 2000 so it is easier to get a driver out after a crash.
“If we try to put it in now, it would be pushing the driver up out of where he wants to sit,” says Garrett in reference to the thicker headrest pad. In looking at better ways to make the headrest, the IRL is investigating various materials, says Casey.
After several severe head injuries in the IRL’s first year, another big issue for chassis manufacturers is safety. Making the cars more crushable on impact is the goal of several 1999 season improvements.
“We’ve worked on a lot of anti-protrusion stuff in the side of the car. We’ve made the radiator vents along the side pods more crushable. We put honeycomb in them so they crush before going into the side of the cockpit,” says Casey. The radiator ducts were previously made from carbon-fiber panels. An extra 3 in. were added to the length of the rear attenuator at the end of 1997 to help it crush on impact and absorb energy.
“We’re in our second phase now. We’re going to start back again and do some more development on the attenuator now. We’re going to redo the thing to try to keep it attached better and make it a more crushable structure so it will work more efficiently than it does now,” says Casey.
Emco Gears Inc. is investigating new ways to attach the attenuator, says Cota. Currently, the attenuator is attached with brackets. Emco is considering casting large sockets into the back of the gear box so the attenuator will fit into it and then be attached from the inside of the rear gearbox.
To make the bell housing more crushable, G Force engineers removed some of the internal bulkheads and lightened it. They also took away metal where they perceived it would improve the ability of the bulkhead to collapse. This also helps from the point of light weight being important strategically in a race.
“Ideally you have your car 15 to 20 pounds below the minimum weight limit so you can carry some ballasts for performance in front or back,” says Dave Amey, G Force. At many races rear wing angles, for example, are mandated to create drag and limit speed. But so far, no such restrictions have been issued for the Indianapolis 500.
“You try to make the car as aerodynamically efficient as you can for the Speedway,” says Amey.
Top secret tires
Tired tires don’t cut it at Indy.
“You have to start with carcass durability. That has to be number one,” says Dick Davis, manager of race tire development for Bridgestone Firestone Inc., Nashville. Teams change tires virtually every pit stop because it takes less time than fueling the car. The tires, Davis explains, have to last as long as a tank of fuel, which equals about 70 track miles. At the end of that 70 miles, the tires must have as much grip as when they were fresh and weighed down by a full fuel tank.
Davis isn’t giving up Bridgestone Firestone’s secret recipe. He says, “That’s pretty confidential. It’s in the compounding and processing of the tire.” Another important aspect of Indy tires is that they must be consistent in grip level and performance from one set of tires to the next. If a replacement set of tires is slightly different, that can change a car’s dynamics, Davis says. One of the most important considerations is the combination of speed and repeatability, says Paul Lauritzen, IRL operations manager for The Goodyear Tire & Rubber Co., Akron, Ohio.
The rules allow for two sets of tires from each of the two manufacturers, a primary and an option tire. Typically, Davis says, the primary tire is something that you know works well, while the option tire may be something that has a bit more grip at the expense of wear.
Each team gets exactly the same tires, whether they be primary or option. It’s not unusual for a team to use a faster option tire for qualifying and then switch back to primary tires during the race. The manufacturers have to make sure teams can do that without changing the car’s dynamics.
“Weather conditions are the reason we bring an option tire. If it gets cool or the track is rubbery, you have a more tractive compound that you can go to,” says Lauritzen.
Tires are redesigned for just about every race, with the Indianapolis 500 typically being the fastest race of the season. In-house departments are arranged so engineers, compounders, technicians, and specification engineers are all in one department at Bridgestone Firestone.
“We’re almost like a mini company here. We’re self-sustaining so we can make decisions on the fly, and we don’t have to worry about conflict with other departments,” says Davis.
Both Goodyear and Bridgestone Firestone keep a watchful eye on their tires.
“At the end of every race we get back every single tire that went out,” says Lauritzen. “With the amount of money that we invest, we can’t afford for them to end up in the competitor’s laboratory.” Goodyear will bring approximately 5,000 tires to the Indy 500.
At Bridgestone Firestone, each tire has a bar code which is assigned to the tire at the building machine. Once scanned into the electronic security system, the tire is tracked “from cradle to grave,” Davis says. Tires are scanned in at the curing press, and each is marked with a hologram. The tires are then sent to the Performance Tire Service Co. warehouse in Indianapolis. They are scanned as they go into the truck, and scanned on the way out. They are also scanned before being distributed to teams at races, and scanned when returned. In this way, Bridgestone Firestone knows where every tire is at any given time. Goodyear also tracks its tires with a bar-coding system.
“There’s millions of dollars worth of technology in these tires, and we want to make sure that we protect that,” says Davis.
Put it to the test
In engineering and tweaking design changes to Indy cars, manufacturers go to great extremes both on and off the track. For instance, when Bridgestone Firestone engineers conduct tests in the ever-shrinking off season, they hit as many tracks as possible. They generally take two teams in case one has mechanical problems. The test team looks for driver feedback.
“The driver has to be able to communicate to us what he’s feeling in the car. If he goes out and runs on an experimental tire and then says ‘well, that didn’t handle very well,’ that doesn’t help,” says Davis. “He has to be able to describe what he’s feeling in the car. There are some pretty good race car drivers out there who aren’t very good test drivers.”
Goodyear runs similar tests using the previous year’s tire as a constant. Engineers look for possible improvements in speed, wear, and repeatability.
Test teams also look at tire temperature on the inside shoulder, the center, and the outside shoulder of the tire to make sure it’s not running hot in one spot and cold in another.
“You have to be a little careful just looking at the stop watch,” says Lauritzen. Other considerations include alignment, camber, and caster which are adjusted based on temperature. Tire inflation is checked, as is stagger on the rear tires. Stagger refers to the fact that one rear tire has a smaller diameter than the other, which helps it turn in a circle. A car’s instrumentation can give tire loads, which determine down force. After all this, track test data is used to influence high-speed durability indoor tests.
Bridgestone Firestone decided on its primary tire for the 1999 Indy 500 race last fall. It ran tests at the end of April to confirm the choice and to determine what the option should be, leaving a month to produce the option selection.
With simulation software like Adams Model software, developed specifically for Indy-style cars by Mechanical Dynamics, Ann Arbor, Mich., and the Ford Racing Advanced Vehicle Team, race teams can weed out certain combinations of components or tire styles. Software to simulate vehicle dynamics has been around for years in the passenger car sector, but just within the last several years a motorsport version was developed by Ford. Teams simulate certain conditions on a computer and then drive a car on a virtual track with the computer logging all data. Engineers can change variables and then rerun the test.
“Essentially, it’s like track testing, but it’s less expensive. We can’t actually get a lap time out of it, but it can tell us whether there’s understeering,” says Andy Brown, chief engineer for Panther Racing. The software records so much data that the Panther team only simulates one turn at a time, so they are not overwhelmed by data. For Indy all the turns are 90° constant radius corners, so data from one turn is sufficient. Simulation testing helps balance the tables between the haves and have-nots, says Amey. When engineering these subtle aerodynamic changes, chassis manufacturers rely on Adams software as a test driver. Amey describes it, “You can basically build a complete computer model of a car, and then on the computer you actually drive it.”
With aerodynamics being the focus of chassis makers, wind tunnel tests are vital. Dallara even owns its own wind tunnel in Italy. It runs on two shifts for 13 hr a day.
“Nothing is equal or fair in life, but there are teams that have huge budgets, and then there are teams that have just enough money to make the grid. That was part of the IRL’s philosophy. As long as they have enough money to buy a car and go race, they can win,” Amey says. According to Amey, there are several teams that still advantage from a larger pocket book, but the IRL’s credo has basically held true.
When Team Cheever hits the track for testing, they’re looking to fine tune.
“The cars are pretty similar to last year, so we ran a known setup and then tried different shocks, different valving, and tried to run different times of the day,” says Owen Snyder III, chief mechanic for Team Cheever. The team is looking to make all the big changes to the car during these tests and not on race day, says Snyder.
Switching gears The Dyno consists of a 502-in. big-block Chevrolet motor that produces 525 lb-ft of torque at 4,500 rpm. Emco developed a gear step-up box which runs the 4,500 rpm though a gear train to 10,500 rpm. The machine loses torque in the process but still comes out with 352 lb-ft at the clutch. The Dyno has a three-plate tilted clutch and throw-out bearings so the transmission can be disengaged and gears changed without shutting down the system. Axles hook into the transmission just as they would on a race car. The axles each connect to a water brake. The speed decreases to about 3,000 rpm and torque increases to almost 800 lb-ft at the axle. With this in mind, the water brakes were set up with a 3:1 planetary gear system that steps up the 3,000-rpm axle speed to 9,000 rpm. Each water brake is strain gaged to read the torque on each axle, and there is a Hall-effect sensor on each brake to measure axle speed. Between the engine and step-up gearbox is a power input shaft which is also strain gaged. “We can work on transmission efficiency by knowing these three numbers,” says Dan Cota, manager, Emco Gears competition racing transmissions and components. The Dyno can be set on a cycle with both axles loaded the same, or with one loaded and one unloaded. Emco engineers also hope to make improvements on Indy cars in other respects by experimenting with gear lubricants, ratios, finishes, and geometries. |
Drivers get early warning The early warning gives drivers a heads up when traversing banks and curves where track lights are not always visible. The brightness of the lights is adjustable to compensate for sunshine or night races. “When they’re traveling at 200 mph, they’re traveling approximately the length of a football field every second. So, if you can give them a second earlier warning before they see the lights on the wall, or the flagmen, that’s maybe 300 or 600 feet they haven’t traveled. They have a chance to get off the throttle, start to get on the brakes, and get slowed down so they don’t get into the mess that’s in front of them,” says Glen Gray, Delphi Delco Electronics Systems motorsports team leader. An electronic receiving module with an antenna was installed in every IRL car. In most cases it is in the front section of the left side pod. The receiving module is connected to a small, two-light unit on the car’s dashboard. “The alternating lights flash like a railroad crossing signal,” says Gray. From the race control stand, an attendant-operated radio control console activates the lights in the cars. The onboard warning lights should also help clear up confusion as to when a car is allowed to make a pit stop. When the pits are open, the director of racing shuts off the blinking lights. “It’s the first onboard light in professional racing that we know of,” says Pierce. The TCR sends messages 20 times per sec. The 900-MHz spectrum frequency hopper radio changes transmitting frequencies 80 times per sec to prevent interference from other 900-MHz radios. The TCR was introduced at the 1998 Indy 500 race. “It only took one or two races before the drivers really started depending on the system,” says Gray. Other racing series have expressed interest in the TCR, according to Gray. “Indianapolis is a difficult track to do because it’s very large and you have a long distance to transmit. Plus you have a lot of obstructions in the infield of the track,” says Gray. To solve this problem, Delphi Delco installed a transmitting antenna different from that used at other tracks. The directional antenna is permanently mounted on the roof of the Indianapolis Motor Speedway stands and is angled toward trouble areas on the back straight. At other tracks, a portable antenna sitting on the race control desk is sufficient. |